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Author Topic: Best Antenna in Limited Space  (Read 457 times)
N1ZHE
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Posts: 68




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« on: October 18, 2003, 08:14:26 AM »

Hi all. I'm about to become the proud owner of a new HF/UHF/VHF rig.

Right now I'm a tech plus, but I expect to pass the General exam at the next VE session in my area.

I live in town on a small lot. I want to get active on as many bands as possible, but I don't have a lot of room or money. I can afford $100 to $150 for an antenna. I intend to run 100 watts only.

I don't mind making my antenna. In fact, I found that for 2 meter FM, my homebrew antenna worked as well as any I have bought!

David, N1ZHE
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K4AXX
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Posts: 87




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« Reply #1 on: October 18, 2003, 08:50:22 AM »

Under a $100, Hy-Gain AVS-18. For about $150 a Hustler 5-BTV. Both are verticals. Or about 20-30 feet of wire and a MFJ 901-B ant. tuner will set you back about $70.
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AA4PB
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Posts: 12897




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« Reply #2 on: October 18, 2003, 09:36:13 AM »

That's not really a question that can be answered very well without knowing your site and knowing what kind of HF operation you are interested in (bands, local/Dx, etc). You need to look at different antenna possibilites in light of the location and where they might be located.

My suggestion would be to start with simple, inexpensive wire antennas for HF. Stick to balanced antennas like a dipole so that you don't have to worry so much about RF grounding. For multiple bands you could use traps or a fan dipole or simply a separate dipole for each band. I probably would not start out trying to find a "do everything" antenna. You have a lot of options using inexpensive wire.

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W8MW
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Posts: 326




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« Reply #3 on: October 18, 2003, 10:26:53 AM »

I agree with AA4PB.  The plain and simple dipole is inexpensive and very forgiving in how you install it. Actually my best successes have been with inverted v dipoles, either single band or multi band using the fan dipole technique, where only one support is needed to get the center up high and the ends can be tied off with rope to any convenient location. In locations where I wasn't lucky enough to have a support such as a tree, I had good luck with chimney mounted masts to get the feedpoint up 10 feet or so above the roof. The old rule of thumb is higher is better.  But I've had satisfactory results with 40 meter inverted vees 20 feet high at the feedpoint with ends only inches off the ground. (It's still best to keep the ends elevated so people and pets can't come in contact).

On another post someone mentioned that some newcomers to HF encounter disappointment because they have great difficulty being heard by other stations. While 100 watts on HF can generate very rewarding results and nice signal reports, the critical variable is the antenna.  Just a gut feel on my part, but I would guess most of the people getting poor performance didn't try dipoles.  The dipole is the standard of reference in all antenna comparisons. Wonder why?

73, Mike W8MW
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G4HZV
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Posts: 102




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« Reply #4 on: October 18, 2003, 12:32:42 PM »

I agree, I'd go for dipoles. They're easy and cheap to build and if they're well balanced, then you shouldn't get much if any TVI.

I had a lot of fun with a single element delta loop at our last house. The advantage of the loop is that you get a low impedance feed on harmonic bands, so my 40m loop worked fine on 20, 15 and 10 also. If you can only fit in a 20m loop, then use 450 ohm ribbon feeder and tune it with an atu. It should work fine on all bands above 20 and you might get it working on 30.
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RobertKoernerExAE7G
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Posts: 1435




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« Reply #5 on: October 18, 2003, 03:46:15 PM »

Congrats on your accomplishment, Tech plus CW.

Home made wire antennas are a lot of fun to build and experiment with.

Since they are so cheeeeap to make, you can have more than one for any band, just to see which one works better.

Bob
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AC5E
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Posts: 3585




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« Reply #6 on: October 18, 2003, 04:02:29 PM »

Actually, David, I would recommend you not spend ANY money on antennas until you have a few antenna books to pore over. The "makings" of an effective and unobtrusive antenna system are pretty cheap - but you can waste a lot of time and effort blindly trying this, that and the other. The books describe antennas that worked for someone else, so they should work for you.

The ARRL's Antenna Book, preferably a late version with the software, is an excellent investment. The ARRL's Antenna Compendium series is also a good investment - as are the RSGB's antenna books. There are usually well thumbed copies of all these, and more, at any well attended hamfest.

And one more thing. Put up a dipole first! Get it to work as well as possible. Then keep it up for a standard to compare your future antenna projects to. It's surprising how many highly touted wonderwires are not even in the same league as a simple dipole.

73  Pete Allen  AC5E


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N6AJR
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Posts: 9910




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« Reply #7 on: October 18, 2003, 05:44:38 PM »

for a store bought verticle I would reccommend the hustler 5BVT for $159 at HRO or better yet make your self a FAN DIPOLE  ( do an elmers search here) and spend $15  for the worlds best cheep antena  73  N6AJR
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KG6AMW
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Posts: 616




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« Reply #8 on: October 18, 2003, 06:37:48 PM »

Go to the Force 12 antenna website and check out the Sigma 5 vertical. Covers all the upper HF bands and is about 9 feet high.  Put up a dipole that covers 40/80 meters and your in business.

KG6AMW
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W6WAT
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Posts: 13




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« Reply #9 on: October 18, 2003, 11:39:55 PM »

David,
Good Luck on your upgrade!  Now, here's a suggestion no one has made yet.  Many have had great success using "screwdriver" antennas for mobile operation.  The W6AAQ design is nearly impossible to beat for convenience and efficiency.  In fact, Don Johnson's design has been copied all over the world, and in fact, there are many so-called "name brands" that are merely rip offs of Don's Screwdriver antenna.  

In your application of limited space perhaps a Screwdriver antenna with a few radials mounted on a homebrew stand or even on a mast or push up pole will surprise you with it's flexibility and performance.  On top of that, you can also use it mobile!  

Oh, and by the way, part of your upgrade should include homebrewing, right?  So, the first thing you can build is a simple remote control box for the screwdriver!

If the Screwdriver doesn't suit you, try a Butternut HF 9VX.  It's a nine band vertical with no traps, and very good performance.  It's been around for several decades, and that should be proof enough that it works.

73
W6WAT
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KF4ZGZ
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Posts: 286


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« Reply #10 on: October 19, 2003, 08:05:15 AM »

Well, I'll answer you with specifics. For a limited space antenna, the best thing I've used is an 88ft. dipole feed with tv twinlead thru a tuner. You could also use 450-ohm ladderline. If you have to bend it or work it around something, that would be OK. This would give you 10-80m with the tuner. If you aren't going to get a tuner, the go with a coax fed resonant dipole. Or (sign!) you can multiband with a fan dipole.

goodluck de Matt, kf4zgz

btw- a 66ft. version of the dipole will give 40m-10m
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AA4PB
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Posts: 12897




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« Reply #11 on: October 19, 2003, 06:27:12 PM »

While the screwdriver is a very good antenna for a mobile installation, I would not recommend it for a fixed installation. It, like all other HF mobile antennas, is extremly inefficient - especially on the lower frequencies. In a mobile you have to live with that. For a fixed installation you don't. There are a multitude of less expensive antennas that will be many times more efficient than a screwdriver.
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W5EEX
Member

Posts: 28




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« Reply #12 on: October 19, 2003, 11:28:42 PM »

I'd suggest a dipole or even a trap or fan-dipole....it doesn't need to be either fancy or expensive. I am using a hidden dipole and I rarely run over 5 watts....usually less....and on CW, I have
worked the world. Today, in the JARTS RTTY contest,
I decided to bump it up to all of 25 watts and in
a couple of hours logged Japan, Hawaii, S.America
and lots of stateside RTTY stations....same old dipole.....they work great....by the way mine is maybe 20 ft up and is hidden under the eaves of the
house....no one can see it and it works great.
73, W5EEX
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KC8VWM
Member

Posts: 3121




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« Reply #13 on: October 20, 2003, 12:19:45 AM »

Dipoles are usually directional and are sometimes difficult to install if you don't have the real estate.

Installing a dipole in an attic or other confined space is just asking for trouble. Antennas work best and have less noise If you can install them "free and clear."

They don't have to be very high. Keep dipoles away from sources of electrical interference. Like house wiring etc.

A would recommend a vertical HF antenna. As Observer has explained, the ionosphere doesn't care what it's reflecting as long as it gets there. May verticals like the "butternut" "Sigma 5" and others are easy to install and will provide an excellent angle of radiation "lift" toward the horizon. This is what will get DX.

The antenna will also be "free and clear" This is the environment antennas work best. Vertical or horizontal or otherwise.

73,

KC8VWM

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